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Where did I go wrong with my wiring? (volume knob not working)

Polvo

Polvo

Jul 27, 2022
38
12
#1
This is a follow-up on my previous post: Trying to turn 2 volume knobs into volume/blend - wiring doesn't match diagram

I had a go at rewiring the bass, and it mainly works ok. But there's a problem with the volume knob - first, it doesn't actually control the volume at all, and second there's a buzzing noise when I touch it. The buzzing suggests a grounding issue but I don't know what... Can anyone help me figure out what's causing the problem?

I more or less followed the wiring diagram below, except for a couple of changes to make the rewiring simpler. Do either of the changes below sound like they would cause the problems with the volume knob?

1. The original wiring had everything grounded to tone, so I left it like that (instead of unsoldering all of those ground wires and resoldering to volume)

2. The tone pot was wired completely differently and I kept it pretty much as is:

  • volume wire goes to the left lug (instead of the middle lug, like in the diagram)
  • left lug also connects to middle lug
  • capacitor is on the middle lug (instead of the right lug, like in the diagram) and then grounded to the top of the pot
  • right lug grounded to the top of the pot

image.png.be8bde366b7842d049edbe1010e3b0b5.png
 
#2
The third lug of the volume pot has to have a good solid connection to ground. Check that first.

Do you have a multimeter? If so, set it to the "continuity" setting, where it beeps if two pieces are electrically connected. Then check to make sure it beeps from the third lug of the volume pot to the jack sleeve.
 
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#4
Just curious, and maybe I'm not reading something right in your description, but it sounds like you have two grounds connected in the Tone Control.

Polvo said:
  • capacitor is on the middle lug...and then grounded...
  • right lug grounded...
Click to expand...
The pot and cap in a passive tone control will always be connected in series with each other, so can only have one ground for the Tone Control.

With two grounds connected, as I think you described, you'd have a parallel circuit within the tone control circuit. That'd cause some wonkiness.

Not important, but I penciled out what I think the description says. The treble would continually be drained off, no matter where the pot is turned, because the cap is always grounded (bassiness for entire turn of pot). When turned fully to the other end, all the bassy volume gets shut off because the pot's end lug is always grounded.

Anyway, maybe wire the Tone Control like the diagram. Just eliminates a possible problem area.
 
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#5
Polvo said:
This is a follow-up on my previous post: Trying to turn 2 volume knobs into volume/blend - wiring doesn't match diagram

I had a go at rewiring the bass, and it mainly works ok. But there's a problem with the volume knob - first, it doesn't actually control the volume at all, and second there's a buzzing noise when I touch it. The buzzing suggests a grounding issue but I don't know what... Can anyone help me figure out what's causing the problem?

I more or less followed the wiring diagram below, except for a couple of changes to make the rewiring simpler. Do either of the changes below sound like they would cause the problems with the volume knob?

1. The original wiring had everything grounded to tone, so I left it like that (instead of unsoldering all of those ground wires and resoldering to volume)

2. The tone pot was wired completely differently and I kept it pretty much as is:

  • volume wire goes to the left lug (instead of the middle lug, like in the diagram)
  • left lug also connects to middle lug
  • capacitor is on the middle lug (instead of the right lug, like in the diagram) and then grounded to the top of the pot
  • right lug grounded to the top of the pot

image.png.be8bde366b7842d049edbe1010e3b0b5.png
Click to expand...
Originally I thought you worked as pictured, which is a functional digram except there is no connection between the jack ground and the pickups ground as each soldered to different pots bodies and there is no connection between them.

As for the wiring method that you described it is complete confusion. That tone circuit is non functional as the tone will be off at all times and act as a strange volume control of that muffled sound.
The tone pot would work if you cut the connection between left lug and center, you also need to float the right lug ( not connect it to anything). Also the two pots bodies need to be connected with a jumper in the shown methods.

On the other note, I think blend pot sucks comparing to two individual volumes... With individual volumes, you get more variations and easier controll. Blend and volume are useful only if you play that "strings" sound by turning volume off, then pluck, then quickly bring the volume up... That is more of a guitar thing like Phil Keaggy.
 
#6
kgbeast said:
Originally I thought you worked as pictured, which is a functional digram except there is no connection between the jack ground and the pickups ground as each soldered to different pots bodies and there is no connection between them.

As for the wiring method that you described it is complete confusion. That tone circuit is non functional as the tone will be off at all times and act as a strange volume control of that muffled sound.
The tone pot would work if you cut the connection between left lug and center, you also need to float the right lug ( not connect it to anything). Also the two pots bodies need to be connected with a jumper in the shown methods.

On the other note, I think blend pot sucks comparing to two individual volumes... With individual volumes, you get more variations and easier controll. Blend and volume are useful only if you play that "strings" sound by turning volume off, then pluck, then quickly bring the volume up... That is more of a guitar thing like Phil Keaggy.
Click to expand...


You’re entitled to your opinion, of course.

But lots of us here prefer a single master volume for ease of use.
 
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#7
I think connecting the left lug of the volume pot it 2 different places to the pan is wrong.
Connect the one corner of the pan to the other one, then send that singular connection to volume left (input).
 
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#8
rojo412 said:
I think connecting the left lug of the volume pot it 2 different places to the pan is wrong.
Connect the one corner of the pan to the other one, then send that singular connection to volume left (input).
Click to expand...
It's cool, they're both electrically the same. The two blend output lugs and volume pot input lug are connected together. It doesn't matter how it was drawn on paper, the idea/result is the same.

Screenshot 2023-05-09 140935.jpg
 
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#9
kgbeast said:
Solder another wire connecting tone and volume bodies.
Click to expand...

Ding ding ding! This was the solution, thank you.

Of course, I'm now faced with the true level of my stupidity, where I finally get all the wiring correct and then realise that I bought the wrong size blend knob for my bass. Goddamn it. Well, at least it I got some soldering practice in. Now off to ebay to buy the right size blend knob...
 
#10
fig said:
Just curious, and maybe I'm not reading something right in your description, but it sounds like you have two grounds connected in the Tone Control.


The pot and cap in a passive tone control will always be connected in series with each other, so can only have one ground for the Tone Control.

With two grounds connected, as I think you described, you'd have a parallel circuit within the tone control circuit. That'd cause some wonkiness.

Not important, but I penciled out what I think the description says. The treble would continually be drained off, no matter where the pot is turned, because the cap is always grounded (bassiness for entire turn of pot). When turned fully to the other end, all the bassy volume gets shut off because the pot's end lug is always grounded.

Anyway, maybe wire the Tone Control like the diagram. Just eliminates a possible problem area.
Click to expand...

This is an interesting one - the tone control is kind of working, but is now more of a switch than a dial. It only has two settings, and at around 60% turn it just jumps from one to the other. I wonder if that's related to the two grounds issue that you mentioned?
 
#11
kgbeast said:
Originally I thought you worked as pictured, which is a functional digram except there is no connection between the jack ground and the pickups ground as each soldered to different pots bodies and there is no connection between them.

As for the wiring method that you described it is complete confusion. That tone circuit is non functional as the tone will be off at all times and act as a strange volume control of that muffled sound.
The tone pot would work if you cut the connection between left lug and center, you also need to float the right lug ( not connect it to anything). Also the two pots bodies need to be connected with a jumper in the shown methods.

On the other note, I think blend pot sucks comparing to two individual volumes... With individual volumes, you get more variations and easier controll. Blend and volume are useful only if you play that "strings" sound by turning volume off, then pluck, then quickly bring the volume up... That is more of a guitar thing like Phil Keaggy.
Click to expand...

I love this bass but can't stand two individual volumes, which is why it's been faced with my cack-handed attempts at rewiring. I'd happily sacrifice a few gradients of tone variation to be able to instantly adjust volume without changing the tone of the bass (or vice versa).
 
#12
kgbeast said:
Originally I thought you worked as pictured, which is a functional digram except there is no connection between the jack ground and the pickups ground as each soldered to different pots bodies and there is no connection between them.

As for the wiring method that you described it is complete confusion. That tone circuit is non functional as the tone will be off at all times and act as a strange volume control of that muffled sound.
The tone pot would work if you cut the connection between left lug and center, you also need to float the right lug ( not connect it to anything). Also the two pots bodies need to be connected with a jumper in the shown methods.

On the other note, I think blend pot sucks comparing to two individual volumes... With individual volumes, you get more variations and easier controll. Blend and volume are useful only if you play that "strings" sound by turning volume off, then pluck, then quickly bring the volume up... That is more of a guitar thing like Phil Keaggy.
Click to expand...

Tell me about it. I don't understand at all the wiring that the bass had from the factory, and rather than disconnect everything and solder it all from scratch, I just frankensteined it. Still don't really understand but it seems to work now (the solution to my initial post was a missing ground from volume to tone).
 

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